Indoor Air Quality Assessments Steve Zemba
Indoor Air Quality Assessments Steve Zemba
Indoor Air Quality Assessments Steve Zemba
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<strong>Indoor</strong> <strong>Air</strong> <strong>Quality</strong><br />
<strong>Assessments</strong><br />
<strong>Steve</strong> <strong>Zemba</strong><br />
Cambridge Environmental
Health Risk Assessment Perspectives<br />
on PCBs in Building Materials and<br />
<strong>Indoor</strong> <strong>Air</strong><br />
Stephen G. <strong>Zemba</strong>, Ph.D., P.E.<br />
(<strong>Zemba</strong>@CambridgeEnvironmental.com)<br />
Cambridge Environmental Inc<br />
58 Charles Street Cambridge, Massachusetts 02141<br />
Phone: 617-225-0810 www.CambridgeEnvironmental.com
Overview<br />
• PCBs synthesized 1929, used in >1,000 products<br />
• Massive occupational exposures (1930’s & 40’s) caused:<br />
– liver failure and chloracne<br />
– but not cancer (Golden & Kimbrough, 2009)<br />
• Standards and guidelines<br />
– OSHA PELs: 500,000 – 1,000,000 ng/m 3<br />
– U.S. EPA Schools: 70 – 600 ng/m 3<br />
Cambridge Environmental Inc 3 www.CambridgeEnvironmental.com
<strong>Indoor</strong> <strong>Air</strong> Screening Levels<br />
EPA’s Recommended Public Health Levels of PCBs in School<br />
<strong>Indoor</strong> <strong>Air</strong> (ng/m 3 )<br />
(www.epa.gov/pcbsincaulk/maxconcentrations.pdf)<br />
Age 1-
PCB Concentrations in <strong>Indoor</strong> <strong>Air</strong><br />
Table 2 PCB Concentrations Detected in Schools (as<br />
obtained from Internet sources or personal communication)<br />
Location<br />
Date Concentrations<br />
(in ng/m 3 )<br />
Lederle Center, U-Mass Amherst 2006 220 – 640<br />
Estabrook School, Lexington, MA 2010 300 – 1,800<br />
Burke School, Peabody, MA 2011 260 – 740<br />
New Bedford (MA) High School 2011 3 – 1,450<br />
Boston (MA) Day Care Center 2012 110 – 200<br />
Cambridge Environmental Inc 5 www.CambridgeEnvironmental.com
PCB28<br />
PCB52<br />
PCB66<br />
PCB74<br />
PCB77 *<br />
PCB81 *<br />
PCB99<br />
PCB101<br />
PCB105 *<br />
PCB114 *<br />
PCB118 *<br />
PCB123 *<br />
PCB126 *<br />
PCB138<br />
PCB153<br />
PCB156 *<br />
PCB157 *<br />
PCB167 *<br />
PCB169 *<br />
PCB170<br />
PCB180<br />
PCB183<br />
PCB187<br />
PCB189 *<br />
Aroclor 1254 (%)<br />
PCB in Caulk (mg/kg)<br />
PCB in <strong>Indoor</strong> <strong>Air</strong> (ng/m 3 *100)<br />
9<br />
8<br />
7<br />
6<br />
5<br />
4<br />
3<br />
2<br />
1<br />
0<br />
PCBs in Denmark Homes<br />
Danish Health Protection Agency, 2012<br />
• 83 PCB-contaminated apartments<br />
• 27 congeners in caulking, indoor air, & serum<br />
• Plotted against Aroclor 1254 composition<br />
16000<br />
14000<br />
12000<br />
10000<br />
8000<br />
6000<br />
4000<br />
2000<br />
0<br />
Aroclor 1254 Caulking <strong>Indoor</strong> <strong>Air</strong><br />
Cambridge Environmental Inc 6 www.CambridgeEnvironmental.com
Mass Percentage of Aroclor<br />
PCB Homologue Groups in <strong>Indoor</strong> <strong>Air</strong><br />
Massachusetts Schools<br />
70%<br />
60%<br />
50%<br />
40%<br />
30%<br />
20%<br />
10%<br />
0%<br />
1 2 3 4 5 6 7 8 9 10<br />
Homolgue Group (Chlorine # in Congerers)<br />
Burke School Boston Child Care Estabrook School<br />
New Bedford HS Aroclor 1254<br />
Cambridge Environmental Inc 7 www.CambridgeEnvironmental.com
Toxicological Values for Risk Assessment<br />
• From U.S. EPA’s IRIS database<br />
– Carcinogenic Potencies<br />
• 1 to 2 kg-day/mg (high-risk/persistence)<br />
• 0.3 to 0.4 kg-day/mg (low- risk/persistence)<br />
– “Non-cancer” Reference Doses<br />
• 20 ng/kg-day Aroclor 1254<br />
• 70 ng/kg-day Aroclor 1016<br />
• 0.0007 ng/kg-day 2,3,7,8-TCDD<br />
• Alternative Approach (Simon 2007)<br />
– Neurological Equivalents<br />
• 8 ng/kg-d Aroclor 1254<br />
• 70 ng/kg-d Aroclor 1016<br />
Cambridge Environmental Inc 8 www.CambridgeEnvironmental.com
Case Study: “Brownfield” Redevelopment<br />
• Mill building conversion to condominiums<br />
– PCB-impregnated floors<br />
– Renovation workers at risk?<br />
• Exposure estimate<br />
– Assume 3.3 mg/m 3 of dust (high level)<br />
– 5.8 mg/kg PCB in dust<br />
– yields exposure to 0.02 μg/m 3 of PCBs<br />
• Acceptable/safe levels<br />
– OSHA PEL: 500 μg/m 3<br />
– More recent studies: 10 μg/m 3 (= 10,000 ng/m 3 )<br />
Cambridge Environmental Inc 9 www.CambridgeEnvironmental.com
Case Study: Child Care Center<br />
• PCB concentrations in indoor air<br />
– 110 – 200 ng/m 3 now<br />
– > 300 ng/m 3 previously<br />
– Exceed EPA guideline of 70 ng/m 3 for 1-2 and 2-3 yr olds<br />
• Questions<br />
– Should center be closed?<br />
– What about < 1 yr-olds?<br />
• Issues and perspectives<br />
– Homologue profile resembles Aroclor 1254<br />
– EPA guidelines derive from toxicity study in monkeys<br />
• Safety factor of 250 applied<br />
• Humans may be less sensitive to PCBs than monkeys<br />
– Nursing infants receive ~ 20 times more exposure than EPA’s<br />
Reference Dose<br />
Cambridge Environmental Inc 10 www.CambridgeEnvironmental.com
Conclusions<br />
• Levels of PCBs measured in indoor air due to building<br />
material sources have been near or greater than recommended<br />
exposure levels<br />
• Actual risks to health may be substantially overestimated (or<br />
conversely, exposure guidelines are highly protective)<br />
• PCBs found in indoor air emphasize the less chlorinated, and<br />
generally less toxic, congeners of the parent mixtures<br />
• PCBs are most likely not as toxic as guidelines imply<br />
• PCB risk assessment methods are uncertain, could be<br />
improved, and will likely evolve<br />
Cambridge Environmental Inc 11 www.CambridgeEnvironmental.com
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